Orthodontic brackets represent a principal component of corrective orthodontic treatments devoted to improving a patient's occlusion. In conventional orthodontic treatments, an orthodontist or an assistant affixes brackets to the patient's teeth and engages an archwire into a slot of each bracket. The archwire applies corrective forces that coerce the teeth to move into orthodontically correct positions. Traditional ligatures, such as small elastomeric O-rings or fine metal wires, are employed to retain the archwire within each bracket slot. Due to difficulties encountered in applying an individual ligature to each bracket, self-ligating orthodontic brackets have been developed that eliminate the need for ligatures by relying on a movable latch or slide for captivating the archwire within the bracket slot.
Conventional orthodontic brackets are ordinarily formed from stainless steel, which is strong, nonabsorbent, weldable, and relatively easy to form and machine. Patients undergoing orthodontic treatment using metal orthodontic brackets, however, may be embarrassed by the visibility of metal, which is not cosmetically pleasing. To improve the cosmetic appearance, certain conventional orthodontic brackets incorporate a bracket body of a transparent or translucent non-metallic material, such as a polymer resin or a ceramic, that assumes or mimics the color or shade of the underlying tooth. Such orthodontic brackets may rely on a metallic insert lining the archwire slot for strengthening and reinforcing the bracket body in the vicinity of the archwire slot. As a result, the appearance of metal in the patient's mouth, while still present to some degree, is less noticeable in ordinary view and, therefore, brackets characterized by a non-metallic bracket body are more aesthetically pleasing. Forming bracket bodies from transparent/translucent material, for example ceramic materials, has become desirable due to the improved aesthetics. However, ceramic materials are brittle and subject to a greater likelihood of fracture in use. Consequently, there is a need for ceramic brackets that are resistant to pressures needed to move teeth to their orthodontically correct positions.
While forming traditional, non self-ligating bracket bodies from transparent or translucent materials has generally improved the aesthetics of these brackets, improved aesthetics for self-ligating brackets has heretofore remained problematic. By way of example, current aesthetic self-ligating orthodontic brackets may use a transparent or translucent bracket body, but continue to utilize a closure member (e.g., ligating slide) made out of metal. One such example of this arrangement is disclosed in U.S. Patent Publication No. 2004/0072117, the disclosure of which is incorporated by reference herein in its entirety. These metal closure members may visibly detract from the aesthetic appearance desired by most patients, especially for the brackets attached to incisors and canines located in the anterior of the oral cavity. These self-ligating brackets have maintained the use of metal closure members generally because of the strength, ductility, and toughness required of such members. Thus, the aesthetics of self-ligating brackets has yet to be fully realized.
Consequently, there is a need for an improved, more fully aesthetic self-ligating orthodontic bracket that overcomes this and other deficiencies of conventional self-ligating orthodontic brackets.